[big_bubba_B]

my 135g tank i bought came with a couple salt water skimmers and a few other things i was wondering if i could use the skimmers on the tank running it fresh water to get rid of the murky film that gets on top of the water ?

 

[Rastapus]

my 135g tank i bought came with a couple salt water skimmers and a few other things i was wondering if i could use the skimmers on the tank running it fresh water to get rid of the murky film that gets on top of the water ?

Protein skimmers will likely not work on your freshwater aquarium due to the density of the water not being sufficient to produce fine bubbles. That being said there are a number of commercially available FW protein skimmers but they are quite expensive and huge. We run a FW protein skimmer on our Koi quarantine system. It works VERY well. You could experiment with the ones you have and add airstones to increase the density of air in the unit. I did see a hobbyist using a seaclone on a FW aquarium and it did remove a little waste.

 

[fkshiu]

I think you mean a surface skimmer rather than a protein skimmer. They are two entirely different things.

This surface skimmer is great for keeping the scum build-up on the water's surface to a minimum:
Hagen Fluval Surface Skimmer

As Rastapus mentioned, protein skimming is only viable in SW at the hobbyist level because the lower surface tension of FW makes foam fractioning extremely difficult without huge pumps.

 

[gklaw]

The simpliest thing is to provide surface agitation. Otherwise, as noted by fkshiu, you will need a surface skimmer.